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Add windows-acl-permissions feature to fix perf issue on windows #902

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1 change: 1 addition & 0 deletions Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -69,6 +69,7 @@ serial_test = "0.5"
default = ["git2"]
sudo = []
no-git = [] # force disabling git even if available by default
windows-acl-permissions = []

[profile.release]
lto = true
Expand Down
64 changes: 45 additions & 19 deletions src/meta/windows_utils.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use std::os::windows::ffi::{OsStrExt, OsStringExt};
use std::path::Path;

use windows::Win32::Foundation::PSID;
use windows::Win32::Security::{self, Authorization::TRUSTEE_W, ACL};
use windows::Win32::Security::{self, ACL};

use super::{Owner, Permissions};

Expand Down Expand Up @@ -137,21 +137,8 @@ pub fn get_file_data(path: &Path) -> Result<(Owner, Permissions), io::Error> {
} as i32));
}

// Assumptions:
// - xxxxx_sid_ptr are valid pointers to SIDs
// - xxxxx_trustee is only valid as long as its SID pointer is
let owner_trustee = unsafe { trustee_from_sid(owner_sid_ptr) };
let group_trustee = unsafe { trustee_from_sid(group_sid_ptr) };
let world_trustee = unsafe { trustee_from_sid(world_sid_ptr) };

// Assumptions:
// - xxxxx_trustee are still valid (including underlying SID)
// - dacl_ptr is still valid
let owner_access_mask = unsafe { get_acl_access_mask(dacl_ptr, &owner_trustee) }?;

let group_access_mask = unsafe { get_acl_access_mask(dacl_ptr, &group_trustee) }?;

let world_access_mask = unsafe { get_acl_access_mask(dacl_ptr, &world_trustee) }?;
let (owner_access_mask, group_access_mask, world_access_mask) =
get_acl_access_masks(dacl_ptr, owner_sid_ptr, group_sid_ptr, world_sid_ptr)?;

let permissions = {
use windows::Win32::Storage::FileSystem::{
Expand Down Expand Up @@ -190,15 +177,53 @@ pub fn get_file_data(path: &Path) -> Result<(Owner, Permissions), io::Error> {
Ok((owner, permissions))
}

#[cfg(all(windows, not(feature = "windows-acl-permissions")))]
fn get_acl_access_masks(
_dacl_ptr: *const ACL,
_owner_sid_ptr: PSID,
_group_sid_ptr: PSID,
_world_sid_ptr: PSID,
) -> Result<(u32, u32, u32), io::Error> {
Ok((0, 0, 0))
}

#[cfg(all(windows, feature = "windows-acl-permissions"))]
fn get_acl_access_masks(
dacl_ptr: *const ACL,
owner_sid_ptr: PSID,
group_sid_ptr: PSID,
world_sid_ptr: PSID,
) -> Result<(u32, u32, u32), io::Error> {
// Assumptions:
// - xxxxx_sid_ptr are valid pointers to SIDs
// - xxxxx_trustee is only valid as long as its SID pointer is
let owner_trustee = unsafe { trustee_from_sid(owner_sid_ptr) };
let group_trustee = unsafe { trustee_from_sid(group_sid_ptr) };
let world_trustee = unsafe { trustee_from_sid(world_sid_ptr) };

// Assumptions:
// - xxxxx_trustee are still valid (including underlying SID)
// - dacl_ptr is still valid

let owner_access_mask = unsafe { get_acl_access_mask(dacl_ptr, &owner_trustee) }?;

let group_access_mask = unsafe { get_acl_access_mask(dacl_ptr, &group_trustee) }?;

let world_access_mask = unsafe { get_acl_access_mask(dacl_ptr, &world_trustee) }?;

Ok((owner_access_mask, group_access_mask, world_access_mask))
}

/// Evaluate an ACL for a particular trustee and get its access rights
///
/// Assumptions:
/// - acl_ptr points to a valid ACL data structure
/// - trustee_ptr points to a valid trustee data structure
/// - Both remain valid through the function call (no long-term requirement)
#[cfg(all(windows, feature = "windows-acl-permissions"))]
unsafe fn get_acl_access_mask(
acl_ptr: *const ACL,
trustee_ptr: *const TRUSTEE_W,
trustee_ptr: *const Security::Authorization::TRUSTEE_W,
) -> Result<u32, io::Error> {
let mut access_mask = 0;

Expand All @@ -223,8 +248,9 @@ unsafe fn get_acl_access_mask(
/// Note: winapi's TRUSTEE_W looks different from the one in the MS docs because
/// of some unusual pre-processor macros in the original .h file. The winapi
/// version is correct (MS's doc generator messed up)
unsafe fn trustee_from_sid<P: Into<PSID>>(sid_ptr: P) -> TRUSTEE_W {
let mut trustee = TRUSTEE_W::default();
#[cfg(all(windows, feature = "windows-acl-permissions"))]
unsafe fn trustee_from_sid<P: Into<PSID>>(sid_ptr: P) -> Security::Authorization::TRUSTEE_W {
let mut trustee = Security::Authorization::TRUSTEE_W::default();

Security::Authorization::BuildTrusteeWithSidW(&mut trustee, sid_ptr);

Expand Down